Ask yourself the following question: How would you ring a doorbell? Would you press it with your finger or your thumb?

The odds are that if you are over 25 years old, you would use your index finger.

But when you ask teenagers, you will find they are more likely to use their thumb.

Why? Because that is the finger this messaging generation uses to type all day, every day on their smartphones. As a result, this "Thumb Tribe" has become significantly more dexterous with the thumb. In fact, according to Intel, teen thumbs have actually started to become thicker and more muscular as a result—a remarkable physiological change in a very short space of time.

The reason this is important is because the new habits that the iGeneration is forming today, driven by the use of new technology during childhood and the teenage years, will be carried through into adulthood. As marketers, we need to understand these behavioral changes and adjust the way we think about creating interactions and building relationships with this tribe now and in the future. Brands that can capture brand loyalty with these young people today set the foundation for longer-term loyalty.

But the communications strategy and messaging that work now probably will not work in the future.

The iGeneration (also referred to as Generation Z) is significantly different from previous generations. People in this demographic have never experienced life before mobile phones and computers. It is not so much part of their life as it is their life.

They are constantly connected. According to the latest Pew Internet research figures, 92% of teens go online daily (largely via smartphones) and twenty-four percent (24%) claim to be online "almost constantly." Their biggest dread is not their elders' FOMO (Fear of Missing Out) but FOBO (Fear of Being Offline).

So what is iGeneration doing with this constant connectivity?

More than any generation before them, they are watching TV online, playing games, and downloading music and video. And, unsurprisingly, a good deal of their online interaction is focused on messaging and social media.

Overall, around seventy percent (70%) of teens use Facebook; however, less than half (44%) of pre-teens who are thirteen years of age are using Facebook. This is called the “Levi's Effect."

The Levi's brand saw a huge decline in the 1990s, driven by kids not wanting to be seen in the same jeans as their parents. Now, as appeal of the traditional social networks like Facebook and Twitter is widening, we are seeing exactly the same effect. Teens are moving to newer social channels not frequented (or even heard of) by their parents—Snapchat, Yik Yak, Vine, Kik, WeChat, and Facebook-owned WhatsApp and Instagram.

These apps have gained rapid traction because messaging is at their core, providing a free means of communication as an alternative to text messaging. But they have also gained traction because they are focused on messaging amongst a smaller group of real friends rather than posts to wider groups of connections.

If you want to get a sense of how social channels are being used by the iGeneration, there is a recent article by thirteen-year-old Soroush Ghodsi in response to the now-famous A Teenager's View on Social Media. To put the Levi's Effect into context, Ghodsi's definition of Facebook is "a way for old people to connect with other old people that they have not seen for decades."

Again, this has some key implications for marketers. Today, the focus of big-brand social activity is on Facebook and Twitter. However, in adulthood, the iGeneration simply will not be found there. Brands need to experiment with other emerging channels in order to understand how best to connect and build a relationship with the Thumb Tribe.

It is not as simple as buying media on these new platforms and assuming it will get through. The iGeneration is also the most media-savvy generation in history. They have been marketed to since birth. As a result, they have developed extremely effective marketing defenses.

One of the ways this manifests itself is that the iGeneration has much lower trust in authority. This means they turn to social media to understand what friends (and even strangers) think of a product or brand rather than relying on official advertising or promotional messaging they receive directly from companies.

Over the last few years, there has been a great deal of focus on the development of brand content and stories as a way to build deeper relationships with consumers. For the iGeneration, this becomes even more important. To stand out in social media, and ultimately in order to be shared, these stories need to be strong and authentic. In fact, content that drives an emotional response in the audience is twice as likely to be shared.

And, of course, the new social platforms will themselves be looking for ways to generate revenue by allowing brands to connect with their audiences. A good example of this is Snapchat's Discover feature. Here brands can create bundles of stories—called “editions" —that disappear after 24 hours. Earlier this year, Discover launched with eleven content partners such as CNN, Cosmopolitan magazine, Mail Online, and National Geographic, all of which are looking to better connect with the iGeneration.

Therefore, it is critical that brands start experimenting now in order to establish the best ways to use these emerging channels to engage their customers. Inevitably, one of these will become the new “Facebook" of the Thumb Tribe.